Usage of property file

You can use the property files when the application needs to get some values which are configured by the users.
For eg, an anti virus application to scan the hard drive in a user defined schedule, user is able to change the schedule interval in a peoperty file as,

SCAN_INTERVAL_IN_HOURS = 10
Here each time the application starts, it will read the value of the key "SCAN_INTERVAL_IN_HOURS".